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huiCfd

@李东岳这台电脑的CPU有点年头了，虽然支持4通道，但是插了两条内存。

huiCfd

CPU型号： Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
系统：Linux mint 19.3
版本：openfoam-6

# cores   Wall time (s):
------------------------
8 552.63
4 623.67
2 814.52
1 1419.05

huiCfd

@东岳感谢东岳老师回复，请问应该用何种循环才能在并行时对所有的cell进行计算呢？

因为并行计算时，函数只在第一个processor里面的domain进行了循环，而所求观测点不在第一个processor的domain里，所以该函数无法返回符合要求的速度。如果要让该函数在其他proessor下也进行循环的话我应该如何修改？或者我应该看哪方面的资料来解决这个问题。
谢谢

huiCfd

processor零，不是o。因为字体原因，0和o看起来很像。

huiCfd

Hello,各位大神，

我在用我自己写的一个求解器并行计算时出现了一个奇怪的问题。这个问题只有在并行计算的时候才会出来，当不并行时没事。问题的具体描述如下：
在我的solver中有一个名为 updateVelocity 的成员函数来获取计算域中某观察点（这个观察点的位置可能会随着时间改变）的速度。
具体如下:

    while (runTime.loop())
    {
        Info << "Time = " << runTime.timeName() << nl << endl;

            #include "CourantNo.H"

        // Pressure-velocity PISO corrector
        {
            #include "UEqn.H"
            // --- PISO loop
            while (piso.correct())
            {
                 #include "pEqn.H"
            }
        }
        laminarTransport.correct();
        turbulence->correct();
        //>>>>>>>>>>>>>Below>>>>>>>
        Nettings.updateVelocity(U,mesh);
        //<<<<<<<<<<<<<Above<<<<<<
        runTime.write();
        Info << "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
             << "  ClockTime = " << runTime.elapsedClockTime() << " s"
             << nl << endl;
    }

    Info << "End\n"
         << endl;

    return 0;
}

这个函数的源代码如下，具体实现形式就是判断每个cell的中心到观察点的距离，然后取出距离观察点距离最近的cell的速度


void Foam::netPanel::updateVelocity(
    const volVectorField &U,
    const fvMesh &mesh)
{
    const vectorField &centres(mesh.C());
    List<vector> fluidVelocities(structuralElements_memb.size(), vector::zero);
    Info << "In updateVelocity, number of mesh is " << centres.size() << endl;
    Info << "In updateVelocity, number of U is " << U.size() << endl;
    scalar maxDistance(1);     
    forAll(EPcenter, Elemi)
    {
        maxDistance = 1; 
        vector nearestCell(vector::zero);
        scalar loops(0);
        forAll(centres, cellI) // loop through all the cells,
        {
            scalar k1(calcDist(centres[cellI], EPcenter[Elemi]));
            if (k1 < maxDistance)
            {
                maxDistance = k1;
                fluidVelocities[Elemi] = U[cellI];
                nearestCell = centres[cellI];
                loops += 1;
                Info << "After " << loops << " times of loop, the nearest cell is " << nearestCell << "to point " << EPcenter << "\n"
                     << endl;
            }
        }
    }
    fluidVelocity_memb = fluidVelocities; // only assige onece
    Info << "the velocity on nodes are  " << fluidVelocity_memb << endl;
}

就是这样的一个简单的函数，但是在并行时却出现了问题。
首先我们来看串行计算的情况：

Starting time loop
Time = 0.01
Courant Number mean: 0.000565 max: 0.0904
smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 2.4007e-06, No Iterations 1
smoothSolver:  Solving for Uy, Initial residual = 0.891308, Final residual = 1.23902e-06, No Iterations 1
smoothSolver:  Solving for Uz, Initial residual = 0.895257, Final residual = 1.31102e-06, No Iterations 1
GAMG:  Solving for p, Initial residual = 1, Final residual = 8.40918e-07, No Iterations 35
time step continuity errors : sum local = 9.50237e-10, global = 1.27782e-10, cumulative = 1.27782e-10
smoothSolver:  Solving for epsilon, Initial residual = 1, Final residual = 0.00445555, No Iterations 1
smoothSolver:  Solving for k, Initial residual = 1, Final residual = 0.004493, No Iterations 1
In updateVelocity, number of mesh is 184320
In updateVelocity, number of U is 184320
After 1 times of loop, the nearest cell is (-0.49375 -0.21875 -0.39375)to point (0 0.05 -0.1)
... ...
After 45 times of loop, the nearest cell is (-0.00625 0.05625 -0.20625)to point (0 0.05 -0.2)

the velocity on nodes are  4((0.226059 -2.8946e-08 -3.59708e-08) (0.226059 3.97379e-08 -4.07855e-08) (0.226059 2.65165e-08 -2.22689e-08) (0.226059 -4.12251e-08 -1.8172e-08))
ExecutionTime = 2.31 s  ClockTime = 2 s

计算的结果没有任何问题，上面的updateVelocity函数也能够顺利的找到4个特定观察点的速度。

但是问题来啦，如果并行计算的话，updateVelocity就没法找到这4个特定观察点的速度了。

Starting time loop
Time = 0.01
Current Number means: 0.000565 max: 0.0904
smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 2.4007e-06, No Iterations 1
smoothSolver:  Solving for Uy, Initial residual = 0.892185, Final residual = 1.24606e-06, No Iterations 1
smoothSolver:  Solving for Uz, Initial residual = 0.895991, Final residual = 1.31577e-06, No Iterations 1
GAMG:  Solving for p, Initial residual = 1, Final residual = 9.93486e-07, No Iterations 34
time step continuity errors : sum local = 1.12264e-09, global = -1.18173e-10, cumulative = -1.18173e-10
smoothSolver:  Solving for epsilon, Initial residual = 1, Final residual = 0.0107252, No Iterations 1
smoothSolver:  Solving for k, Initial residual = 1, Final residual = 0.0106817, No Iterations 1
In updateVelocity, number of mesh is 23177
In updateVelocity, number of U is 23177
the velocity on nodes are  4{(0 0 0)}
ExecutionTime = 0.57 s  ClockTime = 1 s

并行和串行用的是同统一套网格，并行是用 scotch方法分成了八个subdomains
值得注意的是：
在串行计算中：In updateVelocity, number of mesh is 184320
在并行计算中：In updateVelocity, number of mesh is 23177
其中23177就是在processor0中的cell数，下面的是在processor0内的U文件

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0.1";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions      [0 1 -1 0 0 0 0];
internalField   nonuniform List<vector> 
23177
(
(0.225112 5.13224e-05 2.5452e-05)

也就是说，在并行时这个函数只读入梁processor0里面的速度和网格，其他processor1、2、3... 均没有放进来。

请问各位大神有没有人遇到过类似的情况？

huiCfd

问题解决了。将1.0 改为dimless，就可以啦。
具体可以参考这里

huiCfd

@东岳请问是指的openfoam 的编译问题吗？我注意到在程序开始的时候有一个warning，师兄说一般warning都没啥事。但是我看这个warning也是跟IO的控制相关的。感觉有可能在这里就有问题了。

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

--> FOAM Warning : 
    From function static Foam::IOstreamOption::compressionType Foam::IOstreamOption::compressionEnum(const Foam::word&)
    in file db/IOstreams/IOstreams/IOstreamOption.C at line 86
    Unknown compression specifier 'uncompressed', assuming no compression
Create mesh for time = 0


PISO: Operating solver in PISO mode

huiCfd

各位大神好，
在运行我自己写的solver时，遇到了一个关于读取文件的问题。

我需要在一开始的creatField 时，根据我具体的研究对象，写一个名字为 porosityField的volScalarField到"0" 文件夹。我的具体代码如下：

Info<< "Before read porosity field " << "\n" << endl;
volScalarField porosityField
(
    IOobject
    (
        "porosityField",
        runTime.timeName(),
        mesh,
        IOobject::READ_IF_PRESENT, //NO_READ，
        IOobject::AUTO_WRITE
    ),
    mesh,
    1.0
);
Info<< "After read porosity field " << "\n" << endl;

//- update the porosity field
porousZones.updatePoroField(porosityField, mesh);
//- write the porosity field
porosityField.write();

当运行的时候出现了如下的错误：

Before read porosity field 

--> FOAM FATAL ERROR: 
cannot find file "/home/hui/OpenFOAM/hui-v1906/run/Te1/0/porosityField"

    From function virtual Foam::autoPtr<Foam::ISstream> Foam::fileOperations::uncollatedFileOperation::readStream(Foam::regIOobject&, const Foam::fileName&, const Foam::word&, bool) const
    in file global/fileOperations/uncollatedFileOperation/uncollatedFileOperation.C at line 548.

FOAM exiting

根据错误信息可以看出，这一行“Info<< "After read porosity field " << "\n" << endl;” 还没有运行到。所以就是这个读入这个文件的错误，我将 IOobject::READ_IF_PRESENT, 改为IOobject::NO_READ 后再次尝试，但是给出的是同样的错误信息。另外mesh后面的那个1 .0是默认值，去掉后再编译运行也是跟上面同样错误信息。

然而根据这一页的openfoamwiki ，我这样生成的volScalarField 应该没有问题。而且如果用READ_IF_PRESENT 或者NO_READ ，不应该给出找不到文件的错误提示。

MUST_READ – The object must be read from Istream on construction. An error message is produced if Istream does not exist or can't be read.
READ_IF_PRESENT – It reads the object from Istream if Istream exists, otherwise doesn't. An error message is produced only if Istream exists but can't be read.
NO_READ – Don't read the object.

不知道大家有没有类似的经验，帮忙解决一下。
在此提前感谢！

huiCfd

@nbyjn hello，我最近也在做这样一件事，将参数传入到求解器。我想将一个矩阵[100*3]左右的数据传入，不知道您这里可以给我一些提示吗？

huiCfd

@wwzhao 非常感谢指点迷津！

huiCfd

@huiCfd 可能这个适用于of1906

huiCfd

@wwzhao
成功了啊！非常感谢。。
是不可以总结如下经验：

自己编写的类在编译时一定要以lib开头，
然后在编译主程序时，$(FOAM_USER_LIBBIN)后面不能有换行符，
-l之后直接跟自己编译的东西但是要去掉lib

huiCfd

@wwzhao 是的，去掉何不去掉都试过了，
去掉后显示的错误是

 -lm -o /home/hui/OpenFOAM/hui-v1906/platforms/linux64GccDPInt32Opt/bin/dynaPorousNetFoam
/usr/bin/ld: cannot find -llibnetPanel
collect2: error: ld returned 1 exit status
/opt/OpenFOAM/OpenFOAM-v1906/wmake/makefiles/general:140: recipe for target '/home/hui/OpenFOAM/hui-v1906/platforms/linux64GccDPInt32Opt/bin/dynaPorousNetFoam' failed
make: *** [/home/hui/OpenFOAM/hui-v1906/platforms/linux64GccDPInt32Opt/bin/dynaPorousNetFoam] Error 1

没去掉的话跟原来的错误一样，都是undefined reference

huiCfd

@wwzhao 不行。。

huiCfd

@wwzhao
定义也是有的。如下

Foam::netPanel::netPanel
(
    const dictionary&        netDict
)
:   // initial components
    netDict_(netDict),
    porousPropertiesDict_(netDict_.subDict("porousProperties")),
    porosity_(readScalar(porousPropertiesDict_.lookup("porosity"))),
    thickness_(readScalar(porousPropertiesDict_.lookup("halfthickness")))
    // D_(readVector(porousPropertiesDict_.lookup("D"))),  // initial as zeros
    // F_(readVector(porousPropertiesDict_.lookup("D")))  // initial as zeros
{
    dimensionedVector D_(porousPropertiesDict_.lookup("D"));
    dimensionedVector F_(porousPropertiesDict_.lookup("F"));

}

huiCfd

@huiCfd
这个函数后面的const 是用来保护类的成员数据不发生改变。

huiCfd

@wwzhao 赵教授，这两个函数我记得定义了，

    // Constructors
       netPanel
       (
           const dictionary&        netDict
       );

    //- Destructor
    ~netPanel();

但是我有一点不太明白，为什么有的函数后面有一个const，有的没有。例如：
这个虚函数是void funname() const;

void addResistance
        (
            fvVectorMatrix&         UEqn,
            const volScalarField&   nu,
            const fvMesh&           mesh,
            const matrix&   structuralPositions,
            const matrix&   structuralElements
        )const;

而这个函数是 bool funname(); 就没有const了。

        bool isInPorousZone
        (
            const point             x,
            const volVectorField&   structuralPositions,
            const vector&           structuralElementi
        );

const 在括号里面我知道是可以保证传入的参数不变，但是在外边是啥意思啊？

huiCfd

@东岳感谢东岳老师回复，我又看了一下错误提示，出现问题的都是我写的虚函数。

huiCfd

我在想是不是我的这个option里买有格式错误。
我试过将

EXE_LIBS = \
    -L$(FOAM_USER_LIBBIN)\ -lnetPanel \

改为

EXE_LIBS = \
    -L$(FOAM_USER_LIBBIN) -lnetPanel \

结果感觉更错啦

     -lm -o /home/hui/OpenFOAM/hui-v1906/platforms/linux64GccDPInt32Opt/bin/dynaPorousNetFoam
/usr/bin/ld: cannot find -lnetPanel
collect2: error: ld returned 1 exit status
/opt/OpenFOAM/OpenFOAM-v1906/wmake/makefiles/general:140: recipe for target '/home/hui/OpenFOAM/hui-v1906/platforms/linux64GccDPInt32Opt/bin/dynaPorousNetFoam' failed
make: *** [/home/hui/OpenFOAM/hui-v1906/platforms/linux64GccDPInt32Opt/bin/dynaPorousNetFoam] Error 1

huiCfd

@yfclark
这个function, 我已经写到我的class中了，但是问题是在编译求解器时遇到问题“undefined reference”

void Foam::netPanel::addResistance
        (
            fvVectorMatrix&         UEqn,
            const volScalarField&   nu,
            const fvMesh&           mesh_,
            const volVectorField&   structuralPositions,
            const volVectorField&   structuralElements
        )
        {
            const vectorField& centres(mesh_.C());
            forAll(structuralElements,Elementi)
            {
                dimensionedTensor d_(tensor::zero);
                dimensionedTensor f_(tensor::zero);
                transformCoeffs(D_,d_,structuralPositions,structuralElements[Elementi]);
                transformCoeffs(F_,f_,structuralPositions,structuralElements[Elementi]);
                tensor& dvalue = d_.value();
                tensor& fvalue = f_.value();
                const scalarField V = mesh_.V();
                vectorField& Usource = UEqn.source();
                const vectorField& U = UEqn.psi();
        
                forAll(centres, cellI)
                {
                    if(isInPorousZone(centres[cellI],structuralPositions,structuralElements[Elementi]))
                     {
                    tensor dragCoeff = nu[cellI]*dvalue + 0.5*mag(U[cellI])*fvalue;
                    Usource[cellI] -=V[cellI]*dragCoeff & (U[cellI] );
                     }
                }
            }
        
        }

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huiCfd

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